Kassahun, Fesseha (PhD)Yirgashewa, Tewodros2018-07-062023-11-092018-07-062023-11-092006-06http://10.90.10.223:4000/handle/123456789/6999We obtain stochastic di®erential equations for the nondegenerate parametric oscillator with the cavity modes driven by coherent light and coupled to a two-mode squeezed vacuum reservoir. With the aid of these equations, we calculate the quadrature variance and the squeezing spectrum. It is found that the two-mode squeezed vacuum increases the degree of squeezing. It is also found that for ! = 0 the noise in the plus quadrature is completely suppressed. However, the two-mode driving light has no e®ect on the squeezing properties of the cavity modes. On the other hand, using the solutions of the stochastic di®erential equations, we calculate the mean and the variance of the photon number. It turns out that the two-mode driving light and the two-mode squeezed vacuum increase the mean and the variance of the photon number. Furthermore, employing the same solutions, we also obtain the antinormally ordered characteristic function de¯ned in the Heisenberg picture. With the help of the resulting characteristic function, we determine the Q function which is then used to calculate the photon number distribution. Moreover, we calculate the mean, the variance, the photon number distribution for the number of photon pairs, in the absence of the two-mode driving lightenSqueezed Vacuum and Coherent LightThesis